Continuous casting apparatus for aluminum onto metallic strip material



Aug. 16, 1955 R. A. SCHAEFER ET AL 2,715,252

CONTINUOUS CASTING APPARATUS FOR ALUMINUM ONTO METALLIC STRIP MATERIAL 3 Sheets-Sheet 1 Filed June 21, 1951 N mm ma M A0 I J 1AM n6 W 9 AM J PMLFWIBRW Aug. 16, 1955 R. A. SCHAEFER ET AL 2,715,252

CONTINUOUS CASTING APPARATUS FOR ALUMINUM ONTO METALLIC STRIP MATERIAL 3 Sheets-Sheet 2 Filed June 21, 1951 M ri 5 INVENTORS, EAMPH A. SCI/116F619 W/LBfRT H. MORE/SON BY Aug. 16, 1955 R. A. SCHAEFER ET AL 2,715,252

CONTINUOUS CASTING APPARATUS FOR ALUMINUM ONTO METALLIC STRIP MATERIAL Filed June 21, 1951 3 Sheets-Sheet 3 IN V EN TORS, SCH/IEFEE ATTOIQNE vs RALPH 14. W/LBEET f1. MORE/SON United States Patent CONTINUOUS CASTING APPARATUS FOR ALU- NHNUM ONTO LETALLIC STRIP MATERIAL Ralph A. Schaefer, Cleveland, and Wilbert H. Morrison, East Cleveland, Ohio, assignors to Clevite Corporation, a corporation of Ohio Application June 21, 1951, Serial No. 232,702

4 Claims. (C1. 2257.2)

This invention relates primarily to an apparatus for casting and bonding molten metal onto a solid metallic backing strip and rapidly cooling the cast metal in close proximity to the casting zone. More particularly, the invention relates to an apparatus for producing bimetal material by casting a molten metal upon a solid backing metal in strip form and extracting the heat from, and solidifying the cast molten metal in the shortest possible time while bonding it to the backing metal.

An object of the invention is to provide an apparatus which incorporates a sizing die for the cast metal and thus minimizes the thickness of cast metal which must be solidified. Normally in making bimetal strip, an excess of molten metal is cast on the backing material and is then machined to the final desired thickness in a subsequent operation. This casting of an excess thickness of molten metal necessitates extracting a greater amount of heat from the molten metal.

This apparatus is particularly adapted to the bonding of relatively thick layers of aluminum or aluminum alloys onto a steel strip in a continuous process although it is also adaptable for bonding other metals to strip material where rapid quenching of the molten metal is desirable. It is a recognized fact that molten aluminum or aluminum alloys react with ferrous base metals at a rapid rate and form brittle intermetallic compounds which are not capable of cold working or distortion in forming dies for the fabrication of commercial products. In the following description whenever the word aluminum is used, it will mean also aluminum base alloys.

We have found that the present apparatus is especially suitable for bonding thick layers of aluminum up to approximately .l00" thick upon backing material up to approximately .250" thick. The backing material may be steel strip or it may be previously coated with another metal to slow down the reaction rate of the aluminum F with the backing material. The apparatus is especially suitable for use with the method described in pending U. S. application Serial No. 769,616, filed August 20, 1947, now Patent No. 2,611,163 dated September 23, 1952,

where nickel plated strip steel is used as the backing macontrolled by the sizing die (which will be subsequently described) and the strip is held flat by special guide rails and is then quenched by water sprays to reduce the temperature to the solidus point of the aluminum. The speed of the strip through the apparatus is usually maintained between to feet per minute.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of the various mechanical forms in which the principle of the invention may be used.

In the drawings:

Fig. 1 is a cross-sectional view through the continuous casting apparatus showing the bimetallic strip, the molten metal and the quenching streams,

Fig. 2 is an expanded cross-sectional view through the casting apparatus showing the adjustment means upon the backing rollers and upon the abrasion resistant rails along the line 22 of Fig. 4,

Fig. 3 is a view looking upward at the underface of the top die and sizing die,

Fig. 4 is a plan view of the bottom die showing the abrasion resisting rails, the sealing roller with the quench sprays, as well as the back-up rolls,

Fig. 5 is an end view of the apparatus showing the parts in assembled relationship along the line 5-5 of Fig. 1, and

Fig. 6 is a transverse cross-sectional view along the line 66 of Fig. 1 through the strip showing the relationship of the rails, the sizing die and the cast layer.

Fig. 1 shows the cross-sectional view through the apparatus with the die members surrounding the strip showing the strip in position as it passes through the dies during which time the molten aluminum is poured on the strip and quenched from the underside thereof. In this figure, 10 shows a top die member of a material which is resistant to heat and thermal shock, such as a chrome iron alloy which has nickel and 15% chromium with the balance substantially iron. Such a material will be resistant to high temperatures while beingcapable of withstanding thermal shock wherein the die members are at a temperature of the coolant liquid at one part of the die and the molten metal temperature of approximately 1350 F. in another portion of the die.

In addition, the material must be capable of being Welded and machined in order to be fabricated. The bottom die member 11 is of similar material and is made in a piece separate from the top die member. Each die has mounted thereon abrasion resistant rails, rollers and adjustments to be subsequently described, for retaining the strip against the sizing die.

The sizing die 12 shown within and surrounded by the top die 10 is of a material which is resistant to chemical reaction at the temperature of the molten aluminum. This sizing die may be of a composition such as a boride, phosphide, carbon, ceramic or cermet.

The sizing die has an opening across the width of the strip at 17 to permit the flow of metal from the pouring box 18. The molten metal is shown at 14 and is fed by an inlet such as 19 from a casting furnace which heats the metal to the casting temperature. The material feeds by gravity through the casting box into the sizing die above mentioned and contacts the strip at 13. The rear part of the die has imbedded in it a transverse strip or rail 15 which is placed immediately above a sealing roll 16, said sealing roll being mounted adjustably in the bottom die member 11. These two members combine to wipe the strip and to retain the flow of molten metal from a point forward of the strip in the sizing die cavity from leaking out into the furnace and other parts of the sizing die.

The underside of the die 11 has a section beneath the sizing die at which is removed and has in place thereof two rollers 16 and 24 to support the strip as it passes through the die members against the sizing die. The forward end of the sizing die is joined at 51 by a strip contacting the lateral portions of the die which support the roller members.

In addition to these members in the open space heneath the sizing die there is a quenching apparatus consistingof one or more nozzles and 23 capable of projecting a continuous stream of coolant at the undersurface of the strip and outwardly from the molten metal contact point 13 to withdraw the heat from the strip rapidly. Between the quenching nozzles there is a roller 24 having a plurality of contact points with the strip to prevent bowing of the strip while cooling. Roller 24 is adjustably mounted in a bearing member 52 which may be moved in the vertical plane to give the proper clearance between the die members by adjusting screw member 53. Between the die members 10 and 11 there are a plurality of buttons at 27 and 28 which'are dowelled into one of the die members and have a head thereon which causes a spaced separation.

In addition to these members, there are two rails of abrasion resistant material imbedded in each of the die members'and on each side of the die to contact the metallic backing strip and to guide it'through the die members. These rails are clearly shown in Fig. 6 as 87 and 88 and are adjustable from the underside thereof by adjustment handles and 26. This adjustment is to take up warpage or misalignment of the rails caused by heat or pressure. These are also shown in Fig. 2 where the adjustment members are in contact with the underside of the lower rail at 54 and at 55. The adjustment 25 normally is not required and for this reason it isshown in a dotted position.

In addition there is another adjustment on the rearward roller 16 which has an extended casing shown generally at 56 and a cylindrical portion 29, having mounted therein a spring member 57. The roller is adjustable by turning the lower portion 58 into the cylindrical portion 29 by screw threads as seen at 59 which adjusts tension on vertical rod 60 which has attached thereto'a plate 61 in contact with spring 57. The vertical rod 60 contacts a pair of bronze bushing member which surround the axle of the roller.

It can be seen from this adjustment that roller 16 may be given any amount of compression which is *desired to seal the rearward portion of the sizing die from leaking metal therethrough. There is one of these spring adjustment members on either side of the strip.

In addition to the parts mentioned herein, it should be added that the rearward part of the lower die member 11 has a downward extension 62 and a forwardly projecting member 63, which serve as a base or tongue into which may be mounted a pivotal connection in order to permit the entire casting apparatus to be pivotally mounted from the rearward-most section so that any misalignments in the strip may be compensated for by a slight lateral movement in the die members.

In the forward and rearward part of the lower die I members there are two pairs of abrasive resistant metal guides, 94 and 95 at the front and 96 and 97 in the rear. These are shown in Figures 1, 2, 4 and 6. These guide members aid in confining the striplaterally in the event of any misalignment in the strip.

The balance of the apparatus will be explained in connection with Figs. 3, 4, 5 and 6 in that order where like numerals represent the same part throughout th apparatus.

Fig. 3 is a view of the sizing die and top die from the underside thereof showing the sizing die 12,the opening from the top die member into the sizing die 13 which extends across the width of the strip from the right side at 64 to the left side at 63. The sizing die proper extends on the extreme right to a point 65 and has a narrow portion or rail member 66 which extends the entire length of the die from the casting point. The undercut portion'is between the rail 66 and the other rail 67 and extends from the forward end of the. sizing die to the rear casting inlet point. The depth of this cavity which may be seen in connection with Fig. 6', is equal to the approximate thickness of the molten aluminum or aluminum alloys which are to be cast upon the metallic strip backing material. On either side of the top die member there are a pair of identical rails 68 and 69 imbedded therein so as to make their removal possible for assembly, disassembly and replacement, but which are secured therein against the frictional force of the metallic strip as it is being pulled through the die members. On the extreme right and left side at 70 and 71, there are lateral extensions in the form of a U to permit the clamping of the top and bottom die members securely one to another. On the forward end of P the top die member 10 there is a plate 72 extending downwardly to retain a portion of the upper part of the sizing die in order that the sizing die 12 will not pull out from between the die members with the force of the pull rollers upon the strip material being cast.

The plan view of the bottom die member shows a pair of lateral extensions 74 and 75 which are of a shape similar to corresponding members in the upper die member to permit the clamping of the die members together. The lower die member has a section cut away from the underside from 50 to 51 immediately beneath the sizing die in the assembled relationship. In this cavity there are a pair of roller members 16 and 24 mounted on the lateral extensions of the lower die member and adjustably mounted therein with friction bearings as at 52 for the forward roller and 76 for the rearward roller. The rearward roller 16 is of solid construction and con tacts the strip material upon which the aluminum is to be cast to seal the rearward edge against the flow of molten aluminum. The forward roller 24 has a number of contact points, preferably three or more, shown at 77, 78 and 79 which are in contact with the strip and hold the strip against the sizing die.

In addition there are one or more quenching nozzles such as the rearward quench 20 and the forward quench 23 which have an orifice extending across the full width thereof at 80 for the, rearward quenching nozzle and 81 for the forward quenching nozzle. The orifice of the quenching nozzle is directed at an acute angle to the strip and forwardly thereof away from the casting point of the molten aluminum. The open construction of roller 24 permits the continuous quenching of the underside of the strip without disrupting the spray pattern of the coolant.

In addition to the above members, there are the button members 27 in the forward position and 28 in the rearward position, each having a portion which is dowelled into the lower die member. These buttons are used to control the die opening and act as stops when the bolts 84 holding the upper and lower die portions are securely fastened.

On either side of the lower die member at the right and left there are stop or guide members 82 on the left and 83 on the right which extend above the plane of the lower die member and serve to guide the horizontal position which the upper die member should assume in relation to the lower die member.

Fig. 5 is an end view of the apparatus at the exit end showing the assembly of the top die member 10 and the bottom die member 11 having U projections to the left at 71 and to the right at 70 and of bolts 84 to 5 In addition there are rail members briefly mentioned in a description of the-other figures which show the "top rail members at 69 and 68, respectively. Immediately beneath these are the lower die rail members 87 and 88. They grasp the edges of the strip and secure the strip in order that the metal may be cast within ,confined limits.

The forward quench nozzle 23 has an orifice 81 to direct a stream of coolant upon the strip as it emerges from the apparatus. This quench nozzle partially covers roll member 24 which may be seen with its projecting portions 77, 78 and 79 against the lower edge of the strip. This quench nozzle is bolted by arms 89 and 90 to either side of the apparatus by bolts 91 and 92 secured within and from the under side of the lower die member 11.

A cross-sectional view of the strip casting apparatus is shown in Fig. 6 where the relationship of the assembled parts is illustrated. The top die member 10 and the lower die member 11 contact the edges of the strip to top rails 68 and 69 and bottom rails 87 and 88. The sizing die is shown at 12 and the aluminum layer at 86. The strip itself is at 85. The rearward roll which is of steel construction is shown at 16 across the entire width of the strip. The lower rail members. 87 and 88 may be adjusted by a pair of adjusting handles shown in the cross-sectional view as a single adjustment member 26. The top rail is not adjustable.

The rearward roll 16 has bearing members 76 which may be adjusted vertically by a spring adjustment member 60 on either side of the roll. These are connected to a mechanism previously described in connection with The yoke member 62 is seen in this figure Fig. l. beneath the lower die member and extending from the most rearward portion thereof.

In connection with these six views, it may be seen that a strip material generally of ferrous material may have aluminum or aluminum alloys cast thereon and be quenched rapidly. The backing material may be coated with other metals previous to coating with aluminum, but this will not affect the method of using the apparatus. The strip enters the casting apparatus and the rearward side at 93 and exits just in front of the forward quenching nozzle 23. As it flows through the apparatus it passes beneath the sizing die and is sealed by the carboloy rail 15 against the rearward roll 16. The molten metal is cast through an opening of the sizing die in the casting box and is quenched upon the strip with a minimum of reaction between the backing metal and the aluminum or alloys thereof. The forward roller supports the strip against the casting die and prevents the strip from bowing in order to cast a consistent thickness of metal upon the strip material. Because of the rapid changes in condition from a hot strip to a cold strip as rapidly as it occurs, the expansion and contraction of the metals causes severe strain both upon the die members and upon the strip. It must be retained in confined limits so that an even consistent product is produced. As it leaves the apparatus a layer of aluminum preferably from BIO-.060 may be cast upon the strip material. The strip material may be of ferrous material or steel though alloy steels and stainless steels may be used, since the aluminum is quenched rapidly through the steel.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

We claim:

1. In an apparatus for continuously casting and bonding molten aluminum or aluminum alloys at a tempera- .ture of about 1350 F. onto horizontally moving metal strip material, the combination of: a bottom die member of heat and thermal shock resistant material having an opening in one end thereof, spaced apart bottom rails mounted on said bottom die member adjacent said opening for supporting the moving metal strip to close the top of said opening; a pouring box; a top die member of heat and thermal shock resistant material mounted above said bottom die member and underneath said pouring box, spaced apart top rails connected to said top die member for engaging the upper surface of said moving metal strip opposite the location where the bottom rails engage the bottom of the strip, said top die member having a recessed cavity in its underneath surface adjacent the path of said metal strip and having a casting opening therethrough communicating with said pouring box, a sizing die member of heat and thermal shock resistant material and resistant to chemical reaction with the molten material mounted in the recessed cavity of said top die member, said sizing die member having a casting opening registering with the casting opening in said top die member and extending to a location adjacent the top surface of said metal strip as the metal strip moves forward through the die for applying molten metal from the pouring box to the moving metal strip, said sizing die member having a cavity in its underneath surface of the approximate thickness of the metal to be cast on the strip for limiting the amount of molten metal deposited on the moving strip and having a portion extended in the forward direction of motion of the metal strip parallel to said strip and spaced from said strip by the approximate thickness of the metal to be cast on the strip; quenching means mounted a substantial distance below said strip and in a line across the strip and comprising one or more nozzles directed up into the said opening in the said bottom die member and adapted to direct cooling fluid against the underneath surface of said moving strip at a location immediately forward of the location of the casting opening and beneath the extended portion of the sizing die member whereby molten metal cast upon the top surface of the strip is quenched while it is in an enclosure comprised of said top, bottom and sizing die members and said top and bottom rails substantially to prevent chemical reaction between said moving metal strip and said cast metal.

2. An apparatus for continuously casting and bonding aluminum or aluminum alloy to a moving metal strip as set forth in claim 1, further characterized by a transverse rail member extending across the top face of said metal strip in close proximity thereto immediately behind the casting opening in said sizing die to prevent molten aluminum from running along said moving strip in the direction from which said moving strip comes.

3. An apparatus for continuously casting and bonding aluminum or aluminum alloy to a moving metal strip as set forth in claim 2, further characterized by said moving metal strip being fiat.

4. An apparatus for continuously casting and bonding aluminum or aluminum alloy to a moving metal strip as set forth in claim 3, further characterized by said quenching means comprising means for projecting a cooling fluid at an acute angle to the strip and away from the location of the casting opening in the sizing die.

References Cited in the file of this patent UNITED STATES PATENTS 1,995,258 Stockfelth Mar. 19, 1935 1,999,114 Sherwood et a1. Apr. 23, 1935 2,015,154 Palm Sept. 24, 1935 2,022,571 Palm et al Nov. 26, 1935 2,031,795 Salzman Feb. 25, 1936 2,136,394 Poland et al Nov. 15, 1938 (Other references on following page) 8 Williams, May 26, 1942 Mann Mar. 30, 1948 Horn June 17, 1952 Schaefer et a1 Sept. 23, 1952 FOREIGN PATENTS 7 France A9627, 1943 

1. IN AN APPARATUS FOR CONTINUOUSLY CASTING AND BONDING MOLTEN ALUMINUM OR ALUMINUM ALLOYS AT A TEMPERATURE OF ABOUT 1350* F. ONTO HORIZONTALLY MOVING METAL STRIP MATERIAL, THE COMBINATION OF: A BOTTOM DIE MEMBER OF HEAT AND THERMAL SHOCK RESISTANT MATERIAL HAVING AN OPENING IN ONE END THEREOF, SPACED APART BOTTOM RAILS MOUNTED ON SAID BOTTOM DIE MEMBER ADJACENT SAID OPENING FOR SUPPORTING THE MOVING METAL STRIP TO CLOSE THE TOP OF SAID OPENING: A POURING BOX; A TOP DIE MEMBER OF HEAT AND THERMAL SHOCK RESISTANT MATERIAL MOUNTED ABOVE SAID BOTTOM DIE MEMBER AND UNDERNEATH SAID POURING BOX, SPACED APART TOP RAILS CONNECTED TO SAID TOP DIE MEMBER FOR ENGAGING THE UPPER SURFACE OF SAID MOVING METAL STRIP OPPOSITE THE LOCATION WHERE THE BOTTOM RAILS ENGAGE THE BOTTOM OF THE STRIP, SAID TOP DIE MEMBER HAVING A RECESSED CAVITY IN ITS UNDERNEATH SURFACE ADJACENT THE PATH OF SAID METAL STRIP AND HAVING A CASTING OPENING THERETHROUGH COMMUNICATING WITH SAID POURING BOX, A SIZING DIE MEMBER OF HEAT AND THERMAL SHOCK RESISTANT MATERIAL AND RESISTANT TO CHEMICAL REACTION WITH THE MOLTEN MATERIAL MOUNTED IN THE RECESSED CAVITY OF SAID TOP DIE MEMBER, SAID SIZING DIE MEMBER HAVING A CASTING OPENING REGISTERING WITH THE CASTING OPENING IN SAID TOP DIE MEMBER AND EXTENDING TO A LOCATION ADJACENT THE TOP SURFACE OF SAID METAL STRIP AS THE METAL STRIP MOVES FORWARD THROUGH THE DIE FOR APPLYING MOLTEN METAL FROM THE POURING BOX TO THE MOVING METAL STRIP, SAID SIZING DIE MEMBER HAVING A CAVITY IN ITS UNDERNEATH SURFACE OF THE APPROXIMATE THICKNESS OF THE METAL TO BE CAST ON THE STRIP FOR LIMITING THE AMOUNT OF MOLTEN METAL DEPOSITED ON THE MOVING STRIP AND HAVING A PORTION EXTENDED IN THE FORWARD DIRECTION OF MOTION OF THE METAL STRIP PARALLEL TO SAID STRIP AND SPACED FROM SAID STRIP BY THE APPROXIMATE THICKNESS OF THE METAL TO BE CAST IN TEH STRIP; QUENCHING MEANS MOUNTED A SUBSTANTIAL DISTANCE BELOW SAID STRIP AND IN A LINE ACROSS THE STRIP AND COMPRISING ONE OR MORE NOZZLES DIRECTED UP INTO THE SAID OPENING IN THE SAID BOTTOM DIE MEMBER AND ADAPTED TO DIRECT COOLING FLUID AGAINST THE UNDEREATH SURFACE OF SAID MOVING STRIP AT A LOCATION IMMEDIATELY FORWARD OF THE LOACTION OF THE CASTING OPENING AND BENEATH THE EXTENDED PORTION OF THE SIZING DIE MEMBER WHEREBY MOLTEN METAL CAST UPON THE TOP SURFACE OF THE STRIP IS QUENCHED WHILE IT IS IN AN ENCLOSED COMPRISED OF SAID TOP, BOTTOM AND SIZING DIE MEMBERS AND SAID TOP AND BOTTOM RAILS SUBSTANTIALLY TO PREVENT CHEMICAL REACTION BETWEEN SAID MOVING METAL STRIP AND SAID CAST METAL. 